USB (Universal Serial Bus) is a standard serial bus for connecting a computer to a foreign device and also an input/output interface protocol, which is widely used in information products such as personal computers, mobile communication devices and can also be expanded to cameras, digital TVs, video game machines . . . etc.
Following the demands for transmission speed and storing capacity, the transmission speed for USB is up grated from the initial USB 1.0 (Max transmission speed is 12 Mbps), enhanced to USB 2.0 (High Speed)(Max transmission speed is 480 Mbps, and finally to the fastest speed (Super Speed) (Max transmission speed is 5 Gbps) in desire to satisfy consumers' requirements for fast transmission speed and short transmission time especially when a large file is being sent.
Because the USB 3.0 has extremely high transmission speed, problems that never took place before happened. Due to the super high transmission speed, 5 Gbps, each bit shares only 200 picosecond (ps). In contrast, the USB 2.0 has a transmission speed of 480 Mbps and each bit of the USB 2.0 shares 2083 ps when being transmitted. In order to protect the intact of the information being transmitted, there should never be a big gap in transmission time for each bit. However, in high speed digital circuitry, one of the reasons that will affect information accuracy is the near end crosstalk. Near end crosstalk is the electromagnetic coupling interference between two adjacent wires and delays the information reception to each wire, especially when the transmission directions of these two adjacent wires are the same.
With reference to FIGS. 1 and 2, the conventional connector includes multiple terminals 70, a metal housing 71 and a metal casing 72. The terminals 70 is composed of first top signal terminals 700, first bottom signal terminals 701, second top signal terminals 702, second bottom signal terminals 703 and a ground terminal 704. One end of the ground terminal 704 is provided with a metallic baffle 7040. One side of the metallic baffle 7040 corresponds to the first top signal terminals 700 and the first bottom signal terminals 701. The other side of the metallic baffle 7040 corresponds to the second top signal terminals 702 and the second bottom signal terminals 703. The metal housing 71 encloses the terminals 70 and is not connected to the ground terminal 704. The metal casing 72 encloses partially the metal housing 71.
In order to avoid the aforementioned crosstalk, the conventional connector uses the ground terminal 704 to separate the mutually affected first top signal terminals 700 and first bottom signal terminals 701 as well as the second top signal terminals 702 and the second bottom signal terminals 703 so as to direct the near end crosstalk to the ground terminal 704 to reduce interferences caused by the crosstalk. The standard for crosstalk is about 1.2% and the method discussed above reaches only about 0.7% to 1%, which still causes serious crosstalk interference, delays signal transmission and ultimately reduces information accuracy for the USB 3.0.
As the reason set forth, it is crucial to develop a connector to prevent the serious crosstalk interference when the information is being transmitted.